The disclosure relates to a blow-by device of an internal combustion engine comprising an inlet-sided connection socket that can be releasably connected to a coupling piece to which a blow-by line is connected.
A blow-by device of such a type is outlined in documents EP 1 164 264 B1 and EP 1 375 997 B1 of Applicant. Accordingly, during the operation of an internal combustion engine the crankcase, on account of leaks in the region of the piston seal, is filled with combustion gases that mix with oil vapors and generally are referred to as blow-by gases. By the stroke of the pistons of the internal combustion engine pressure is additionally applied to those blow-by gases, resulting in a pulsating volume flow. As the volume flow includes noxious hydrocarbon compounds and moreover is comparatively high—even with an optimum sealing of the piston rings the blow-by gas volume flow may amount to approximately 0.5 to 2% of the total gas volume flow—measures are required in order to prevent those gases from escaping into the environment.
For this purpose, it is generally known to provide for vacuum-controlled crankcase ventilation. In such ventilation the blow-by gas flowing from the crankcase is first guided over an oil separator. The blow-by gas then passes through a pressure control valve (blow-by valve) and reaches an intake passage at a feed area of the internal combustion engine for after-burning.
Frequently the oil separator is a cyclone separator from which a large portion of the oil is returned to the oil pan.
The pressure control valve preferably limits and keeps the vacuum in the crankcase constant. Upon a standstill of the engine the pressure control valve is open. In idling or coasting operation, which is characterized by a vacuum in the suction pipe and little blow-by gas, the pressure control valve is closed. When the load is higher, more blow-by gas occurs and the pressure control valve is opened in order to maintain the negative pressure approximately constant.
A problem exists in that particularly at low ambient temperatures hot blow-by gases encounter the cold suction air, resulting in condensation in the feed area due to a rapid cooling down in the area where the two gas flows are joined, which may lead to icing in this area. Likewise, icing in the area of the pressure control valve is possible. In order to avoid such icing in components through which blow-by gas flows, they are heated up via a heater. Solutions of that kind are already described in DE-AS 24 32 782, EP 1 314 869 B1, and DE 195 18 712 A1. Those heaters may be implemented, e.g., as conventional electric heaters. The prior art initially mentioned proposes to make use of PTC resistive elements as heating elements.
The heating of blow-by gases or of components through which those blow-by gases flow is also known from documents U.S. Pat. No. 4,922,882 and U.S. Pat. No. 4,321,121.
A problem of all of these solutions consists in that e.g. during maintenance work on the engine it may be forgotten to re-connect all of the fluid lines, particularly the blow-by line that connects the crankcase and the intake passage. For example, the connection between intake passage and blow-by heater or the connection between the crankcase and the aforementioned heater, which is usually formed by a tube, thus may not be made. On account of such accidental separation the blow-by gas volume flow is released to the environment—this is to be avoided with regard to possible environmental pollution. For the functioning of the internal combustion engine it also is problematical that the suction side of the internal combustion engine then sucks in “false air” and the engine management can no longer work in an exhaust gas optimized manner.
To overcome such a disadvantage EP 2 418 361 A2 proposes to execute the blow-by device with an electrically conductive unit contacted by way of an electric connector. The contacts may only be established if all fluid lines are connected mechanically in a predetermined manner.
To realize this, in the known solution, a connector collar for receiving a connector is formed on a coupling piece, insertion of the connector only being possible if a blocking element is moved to a release position. In an example, this adjustment of the blocking element is performed by a carrier on the coupling piece, the carrier being only in engagement with the blocking element if the fluid connection is established properly.
A disadvantage of such a solution is that considerable effort with regard to the configuration of the device is required in order to form a connector collar, a carrier and the blocking element on the coupling piece and an associated connecting piece. Furthermore, the connector is inserted crosswise to the axis of the fluid line, so that also the effort in assembling the device is considerable.
Moreover, solutions are known in which the sucking of “false air” is detected by an airflow sensor, so that the signal of the airflow sensor is indicative of a mechanical connection in the area of the blow-by device that is not properly made. Solutions of that kind, however, may only be used in lines with a comparatively large cross-section.
DE 10 201 0 020 844 discloses a method for controlling the blow-by function of an internal combustion engine. The blow-by device has a heater for heating the blow-by gases. In so doing, the power consumption of the heating elements is monitored and in case of a deviation of the power consumption from a predefined characteristic, it is concluded that blockage has occurred or a connection is not properly formed.
Such a solution requires considerable control effort.